Raman Spectroscopic Studies on Graphene Oxide – Europium Nano Composites

Abstract

Graphene based nano composites are receiving much importance in recent years due to the two-dimensional topology, high carrier mobility, luminescent nature, and ultra wide band gap transition. Here graphene oxide is prepared by modified Hammers method. Resultant residue of dark yellow color is filtered using Watt man No. 1 filter paper and is further cleaned by washing several times with 5% HCl solution and de-ionized water. Unexfoliated oxide is eliminated from the sample by ultra-sonication procedure for 30 minutes followed by micro-centrifugation under 4000 rpm for another 30 minutes. Vacuum annealing is done at sample at 60OC for 12 hours to get black graphene oxide powder and is labelled as Sample4. Europium (III) nitrate is added to 3g each of graphene oxide powder in 0.1g, 0.2g, and 0.3g concentration respectively labelled as Sample1, Sample2, and Sample3. Uniform mixing is done in composite samples. Morphological properties are analyzed through SEM. Surface topology of GO is like thin folded sheet, while that of Eu-GO is like that of spreading small nano materials on folded surface. Average particle size distribution is found to be 79.09 nm. Chemical composition and stotiometric ratio of different elements in the composites are quantitatively shown by EDX analysis. Raman spectra for Samples 1, 3, and 4 are shown. We can see that no shifting of peaks are observed in composites with respect to pure GO is an evidence of stable sp2 hybridisation and rigid oxygenated functional groups.